Automatic refrigerator control



Dec. 6, 1955 D. E. HlLLlKER I 2,725,723

AUTOMATIC REFRIGERATOR CONTROL Filed April 28, 1953 2 Sheets-Sheet lInventor: Donald E. Hilliker,

l-lis Attorney,

Dec. 6, 1955 HILLIKER AUTOMATIC REFRIGERATOR CONTROL Filed April 28,1953 2 Sheets-Sheet 2 United States Patent AUTOMATIC nnnnionnnroneonrnor Application April 28, 1953, S erial No. 351,559 20 Claims. (Cl..62 ---4) My invention relates to refrigeration apparatus andpertainsmore particularly to automatic controlling means therefor.

The primary object of my invention is to provide a new and improvedautomatic refrigerator controlling means for maintaining a substantiallyconstant refrigerator temperature and for initiating defrostingoperations.

Another object of my invention is to provide a new and improvedautomatic refrigerator controlling means including a spring poweredtiming mechanism and adapted for initiating defrosting operations as afunction of cumulative door opened time during unit running time.

Still another object of my invention is to provide with an automaticrefrigerator control including a spring powered timing mechanism, meansadapted for winding the timing mechanism in response to refrigeratordoor openings.

Further objects of my invention will become apparent as the followingdescription proceeds and the features of novelty which characterize myinvention will be pointed out with particularity in the claims annexedto and forming part of this specification.

In carrying out the objects of my invention, I provide an operating armmovable between a refrigerating unit operating position and a defrostingposition. Temperature responsive means actuates the arm to the unitoperating position at a predetermined normally high temperature andtoward the defrosting position at a predetermined low temperature.Additionally, I provide a spring powered timing mechanism adapted forbeing wound in response to refrigerator door openings. The timingmechanism is stopped when either the refrigerator door is closed or thearm is out of the unit operating position. Normally when the arm isactuated toward the defrosting position, it is intercepted at anintermediate unit deenergizing position by means operated by the timingmechanism. Upon the lapse of a predetermined cumulative amount ofrunning time of the timing mechanism the last-mentioned means actuatestherarm to the defrosting position. In the defrosting position, the armis attracted by a magnet. At a predetermined abnormally high,temperature the temperature responsive means overcomes the magnet andreturns the arm to the unit operating position.

For a better understanding of my invention, reference may be had to theaccompanying drawing in which:

Fig. 1 is a fragmentary sectional view of a refrigerator cabinetillustrating my control mounted therein and the cooperation between mycontrol and the refrigerator door;

Fig. 2 is an enlarged fragmentary detailed perspective view of mycontrol;

Fig. 3 is a plan view of my control illustrating the operating armtherein in a unit operating position;

Fig. 4 is a plan view of my control illustrating the operating arm in adefrosting position; and

Fig. 5 is a fragmentary plan view of my control illusice trating the armin an intermediate unit deenergizing position. V i

In Fig. 1 is partially shown a refrigerator cabinet including an outercase 2 and a spaced apart liner 3. Provided in the space between theouter case and liner is suitable heat insulation designated 4. Closingthe space between the edges of the outer case and liner is a breakerstrip 3a. The liner 3 defines a food storage compartment 5 wherein islocated an evaporator (not shown) for cooling the contents of the ,foodstorage compartment. Provided for closing an access opening to the foodstorage compartment is a door 6 supported .by suitable hinging means(not shown) secured to theouter case2. Mounted on the door 6 and adaptedfor sealing the food storage compartment 5 when the door, is closed is agasket 7. Suitably mounted in the space between ,the outer case 2 andthe liner 3 and directly behind the front portion of the breaker strip3a is a preferred embodiment of my automatic refrigerator controlgenerally designated 8 and shown in detailin Figs. 2-5.

As seen in Figs. 3-5, the control 8 is mounted on a base 9 formed of asuitable insulating material and includes an operating arm 10. Theoperating arm 10 is formed of magnetic material and is provided at therearward end thereof with an extension 11. The extension 11 projectsthrough an aperture 12 in a vertical end portion 13 of a bracket 14fixedly mounted on the base 9. Straddling the extension 11.is a pairofknife-edges 15; The knife-edges .15 are disposed in reentrant portions16 formed in the vertical end portion 13' of the bracket 14 wherebypivotal movement of the arm 10 is permitted about the knife-edges.Secured to the outer side of the operating arm 10 is an insulativeL-jshaped member 17 including an arm 18disposed in a hook portion 19formed at the upper end of a vertically extending resilient contact arm20 suitably secured to the base 9. Carried on one side of the hookportion 19 of the contact arm 20 is one of a pair of refrigerating unitcontacts 21. Carried on the side of the hook portion 19 opposite thecontacts 21 is one of a pair of defrost contacts 22. When the arm ,18 ofthe insulative member -17 is so positioned that it causes the unitcontacts 21 to close in the manner shown in Figs. 2 and 3, the operatingarm 10 carrying the insulative member is in a first or refrigeratingunit operating position and a refrigerating unit (not shown) isenergized for lowering the temperature of the evaporator in the foodstorage compartment of the refrigerator. When the armlta of theinsulative member 17 is so positioned that it opens the contacts 21 andcloses'the defrost contacts 22 in the manner shown in Fig. 4, theoperating arm 10 is in a second or defrosting position and the unit isdeenergized and defrosting means such as aheater .(not shown) isenergized whereoy frost formed in therefrigerator is melted. When thearm 18 of the insulative member 17 is so positioned that it maintainsboth pairs of contacts 21 and 22open in the manner shown in big. 5, theoperating arm iii stands in an intermediate unitdeenergizing position.

Provided for cooperating with the operating arm it; to bias theoperating arm to either the unit operating posh tion or the defrostingposition is a toggle spring 23. 'i'he two legs of the toggle spring 23each include a depression 24. Pivotally seated in one of the depressions24 is a knife-edge 25 formed on a forwardlyextending arm 2e bent off theside of the operating arm it). Pivotally seated in the other depression24 is an end of a resilient arm 27 suitably secured to an upstandingportion 28 of the base 9. Adjustments to the tension of the toggtespring 23 is accomplished by turning an adjustment screw 29 which isthreaded in a second upright portion 35; of thebase 9. Turning the screw.29 inwardly increases the tension of the toggle spring .23 andtherefore the force with which the operating arm is biased. Turning thescrew 29 outwardly relieves the tension of the spring 23 and reduces thebiasing elfect thereof on the operating arm. By adjusting the tension ofthe spring 23 in the just-described manner, the normal operatingtemperature to be maintained in the food storage compartment of therefrigerator may be independently determined.

Provided for opening and closing the unit contacts 21 in accordance withthe temperature of the evaporator thereby to maintain a substantiallyconstant normal temperature in the food storage compartment istemperature responsive means generally designated 31. The temperatureresponsive means 31 includes a metal bellows 32 mounted on a verticalside portion 33 of the bracket 14 and a tube 34 connecting the bellowswith a volatile fluid containing bulb (not shown) disposed in heatexchange relationship with the evaporator. In accordance with thetemperature change at the evaporator, the saturation pressure of thefluid in the bulb results in corresponding longitudinal expansion andcontraction movements of the bellows 32. A pin 35 is interposed betweenthe bellows 32 and the operating arm 10. On the side of the operatingarm 10 opposite the bellows and pin is a coil spring 36. One end of thecoil spring is disposed in a spring seat formed by a plurality ofprojections 37 formed on the arm 10. The other end of the spring 36 isseated in a cap 38. The cap 38 is formed to include a lateral extension39 adapted for sliding movement in a horizontal slot 40 in the verticalend portion 13 of the bracket 14 whereby the cap is rendered movablehorizontally but prevented from rotating. Threaded in the cap 38 is anadjustment screw 41. The adjustment screw 41 is rotatable in andsuitably prevented from moving longitudinally with respect to anothervertical side portion 42 of the bracket 14. In this arrangement, thespring 36 causes the operating arm 10 and the pin 35 to follow thecontractive movements of the bellows 32. In turn, expansive movements ofthe bellows 32 actuates the pin 35 to move the operating arm against thebias of the coil spring 36. The compression of the spring 36 and,therefore, the expansive movements of the bellows 32, are determined bythe setting of the adjustment screw 41. Turning the screw 41 in onedirection moves the cap 38 inwardly for increasing the compression ofthe coil spring 36 and turning the screw 41 oppositely moves the capoutwardly for reducing the compression of the coil spring 36. Providedfor facilitating the turning of the adjustment screw 41 is a knob 43. Asseen in Fig. l, the shank of the screw 41 is adapted for extendingthrough the side wall of the liner 3 and the knob 43 is adapted forbeing secured on the shank of the screw on the inner side of the liner 3or in the food storage compartment 5. Adjustments to the control byturning the knob 43 are intended to be made by the person using therefrigerator and suitable legends may be provided on the liner behindthe knob to indicate the temperature to be expected to be maintained bythe control 8 at various settings of the knob.

In the operation of the arrangement described to this point an increasein temperature at the evaporator results in an increase in pressure ofthe fluid in the control bulb and corresponding expansion of the bellows32. At a predetermined normally high temperature determined by thesetting of the knob 43 and the adjustment screw 29, the bellows 32exerts a force on the operating arm 10 through the pin 35 sufiicient forovercoming the bias of the toggle spring 23 and the coil spring 36 androtating the operating arm clockwise about the knife-edges toward theunit operating position of the operating arm. Movement of the operatingarm 10 in this manner results in the toggle spring 23 snapping the armto the unit operating position and in the insulative member 17 closingthe unit contacts 21. This results in operation of the refrigeratingunit whereby the temperature of the evaporator is reduced. Reduction ofthe evaporator temperature effects reduction in pressure of the controlbulb and corresponding contraction of the bellows 32. Upon reduction ofthe evaporator temperature to a predetermined low temperature alsodetermined by the setting of the knob 43 and the adjustment screw 29,the contraction of the bellows is such that the spring 36 is able toovercome the effects of the pin 35 and the toggle spring 23. As aresult, the operating arm 10 moves out of its first position and theinsulative member 17 carried thereon opens the unit contacts 21 forstopping the refrigerating unit.

Thereafter, the toggle spring 23 actuates the operating arm 10 towardits second position wherein the insulative member 17 would close thedefrost heater contacts 22 and thereby energize the heater. Since it isnot desirable to energize the defrost heater after each cycle of unitoperation, I have provided means for intercepting the operating arm atthe intermediate unit deenergizing position shown in Fig. 5 when theevaporator temperature decreases to the predetermined low until thattime when it is desired that a defrosting operation be initiated.

In the preferred form of my invention, defrosting is initiated as afunction of refrigerator door opened time during unit running time. Toaccomplish this, I have pro vided a spring powered timing mechanism gnerally designated 44. The timing mechanism 44 includes a main shaft 45having secured thereto the inner end of a main spring 46. The outer endof the main spring 46 is formed as a detent 47 for cooperating with aplurality of inwardly projecting ridges 48 formed spacedly on the innerperiphery of a rotatable spring case 49 housing the main spring. Thisarrangement permits the detent 47 to snap past the ridges 48 whenexcessive torque is developed in the main spring and thereby providesfor a constant spring torque. Secured to the spring case 49 is a ratchetwheel 56. Suitably secured to the base and provided for engaging theratchet wheel to prevent unwinding of the main spring through the springcase is a pawl 51. Cooperating with both the pawl 51 and the ratchetwheel 50 is another pawl 52. The pawl 52 is carried by a plunger 53adapted for having its forward end extend through the front face portionof the outer case 2 and cooperate with the refrigerator door 6 in themanner shown in Figs. 1 and 2. Carried on the plunger 53 between aspring seat 54 secured thereon and an upright bracket 55 formed off thebase 9 is a coil spring 56 sufiiciently strong to overcome the mainspring 46. In this arrangement, the spring 56 is compressed and the pawl52 is maintained in the position of Fig. 2 in which it is in engagementwith the pawl 51 when the door 6 is closed. When the door is opened, thespring 56 actuatcs the plunger 53 forwardly or outwardly from therefrigerator cabinet causing the pawl 52 to ride down the pawl 51 andinto engagement with the tooth of the ratchet Wheel engaged by the pawl51 and displacing the ratchet w ecl 50 and the spring case 49 one toothspace thereby to increase the torque of the main spring 46. Thus, thetiming; mechanism 44 is wound in response to refrigerator door openings.

Controlled relief of the torque in the main spring 46 of my timingmechanism 44 to provide a timing operation is effected in much the sameway as in most spring powered timing devices. Fixed on the main shaft 45is a main pinion 57 meshing with a gear 53 rotatable on a second shaft59. Secured to the gear 58 is another pinion 60 meshing with anothergear 61 rotatable on the third shaft 62. Secured to the gear 61 is anescapement wheel 63. Cooperating with the escapement wheel 63 is a pairof pallets 64 carried on the tines of a first bifurcated end 65 of anescapement lever 66. A pivot pin 67 passing through and secured to theescapement lever 66 adjacent the first bifurcated end 65 serves as afulcrum for the escapement lever. The escapement lever 66 additionallyincludes a second bifurcated end 63 adapted for receiving andcooperating with a pendent pin 69 carried by a balance wheel 76 adjacentthe periphery thereof. The balance wheel 70' is secured to a: pivot pin71 to which is also secured the inner end of ahairspringna The outer endof the hair spring 72 is suitably secured to a base mounted bracket 73.'In this arrangement, the hair spring72 oscillates the balance wheel 70which in turn oscillates the escapement lever 66 to provide cooperationbetween the escapement wheel 63 and the pallets 64 thereby to permitthrough the gear train between the pinion 57 and the escapement wheel 63timed controlled rotation of the pinion 57 by the main spring- 46. 7

Provided for stopping the timing mechanism 44 when the operating arm 10is out of the first or unit operatingposition is a braking element 74suitably mounted onthe operating arm and adapted for cooperating withthe balance wheel 70. The braking element 74 engages the periphery ofthe balance wheel 70 inthe manner shown in Fig. 4- whenever theoperating arm 10 is not in the first position for thereby stopping. thetiming mechanism. As seen in Fig. 4, the braking element 74 engages thebalance wheel periphery at an off center location. Therefore, when theoperating arm 10 is subsequently returned to its first or unit operatingposition, the braking element 74 disengages the balance wheel peripherywith a wipingaction. This wiping action provides the impetus necessaryfor satisfactorily starting the'balance wheel to oscillate and therebyrestart the timing mechanism 44.

Provided for stopping the timing mechanism 44' when the refrigeratordoor 6 isclosed is a braking element 75 suitably mounted on the plunger53 and adapted for cooperating with the balance wheel 70. The brakingelement 75 engages the periphery of the balance wheel 70 in the mannershown in Fig. 2 whenever the refrigerator door 6 is closed and theplunger 53 is actuated inwardly. As seen in Fig.- 2, the braking element75 also engages the balance wheel 70 at an off center location.Therefore, whenever the refrigerator door 6 is opened and'the unit isoperating, the braking element 75 disengages the balance wheel with awiping action and thereby provides 'the impetus necessary for startingthe-balance wheel" to oscillateand thereby restart thetiming mechanism.

Bent out of the pinion 57 is an upstanding lug 76. Carried rotatably onthe main shaft in spaced relationship to the pinion 57 is a cam 77formed to include a large recess 78. A stud 79 suitably fitted andretained in the cam 77 at a point substantially diametrically oppositethe recess 78 includes a lug portion 80 which projects through the camtoward the pinion and is adapted for being engaged by the upstandinglug. 76 on the pinion; The stud 79 is in effect a hammerelementandconnected between the stud and the rear end-portion lfi'of the bracket14isa coil spring 81. The purpose for thisarrangenient will be seenhereinafter. Since the timing mechanism 44 is stopped by the brakingelements 74- and 75, when either the operating arm 10 is out of the unitoperating position thereof or the refrigerator door 6is closed,-thepinion'57' rotates only when the refrigerator door is open and the unitis operating. Rotation of the pinion 57 causes the lug 76 carriedthereby to engage andpush the lug portion 80 of the stud 79 fitted inthe cam-77. Thus,-rotation of the pinion 57 causes angular displacementor rotation of the cam 77.

The operating arm 10 carries a stop'82 and durin'g normal operation anduntil an elapse'of a predetermined cumulative amount of-runningtime ofthe timing'mechanism 44, the recess 78 in the cam 77 is not aligned withthe'stop 82. Accordingly,-when" the temperature of the evaporatordecreases to-the predeterminedlow temperature and the operating arm 10is actuated out of its first-or unit operating position and toward thedefrosting position by the springs 23 and 36, the stop 82 engagestheperiphery of the cam and the operating arm is thereby intercepted at theintermediate unit deenergizingposition of Fig. 5. When the operatingarmis in the unitdeenergizing position, the insulative-member17 carriedthereon maintains both the unitcontacts 21 and thedefrost'heatercontacts 22 open and the braking element 74, also carried by theoperating arm, engages the balance wheel 70 to stop the timing mechanism44. 7

Subsequently, when the temperature of the evaporator increases to thepredetermined normally high temperature, the bellows 32 expandssufficiently for overcoming the springs 23 and 36 and returning theoperating arm 10 to its first position wherein the unit contacts 21 areclosed and the braking element 74 disengages and exerts a startingimpetus on the balance wheel 70, which will be effective for restartingthe timing mechanism only if the door is open and the other brakingelement 75 is disengaged from the balance Wheel.

Upon the lapse of a predetermined cumulative amount of running time ofthe timing mechanism 44, the cam 77 is driven to the position thereofshown in Fig. 3, from which position the spring 81 snaps over center. Insnapping over center, the spring 81 causes the hammer element 79 toengage the outer end of a semi-circular arm 83 secured to the operatingarm 10. Thus, the operating arm 10 is actuated or driven out of thefirst or unit operatting position. When the hammer element 79 engagesthe semi-circular arm 83, the recess 78 in the cam 77 is aligned withthe stop 82 carried by the operating arm.

' Therefore, the stop 82 becomes seated in the recess 78 and theoperating arm 10 is permitted to move to the second position thereofshown in Fig. 4, in which position the insulative member 17 opens theunit contacts 21- and closes the heater contacts 22 for therebyinitiating a defrosting operation.

When the operating arm 10 is in its second or defrosting position, thebraking element 74 carried thereby engages the balance wheel 79 andstops the timing mechanism Additionally, the forward extremity of theoperating arm 10 moves into a concentrated field of attraction of apermanent magnet 84 secured to the side of a bracket 85 on the base 9.The magnet 84 attracts the operating arm and determines the temperatureof the evaporator at which the bellows 32 will be effective forterminating the defrosting operation and returning the operating arm tothe unit operating position. Threaded into the bracket 85 andcooperating with the operating arm It? is a set screw 86. The set screw86 limits the movement of the operating arm toward the magnet 84 andprovides for adjustment of the space between the magnet and theoperating arm. By adjusting the space and, therefore, the attractionbetween the magnet and' the operating arm, independent adjustment of thedefrosting temperature or the temperature at which defrosting willterminate may be obtained.

Upon attainment of a predetermined abnormally high temperature at theevaporator suflicient for melting all the frost thereon and determinedby the setting of the screw 86, the force exerted on the operating armby the bellows 32 becomes sufficient for overcoming the influence of themagnet 84- and the toggle spring 23 on the operating arm 1! Thereafter,through the pin 35, the bellows returns the operating arm to its firstposition thereby terminating the defrosting operation and closing theunit contacts 21 for initiating a normal refrigerating cycle.

As seen in Fig. 4, all of the tension in the spring 81 is not relievedwhen the stop 82 is in the recess 78. That is, when the operating arm 16is in the defrosting position the stop 82 limits the rotation of the cam77 at the position of Fig. 4 and the cam is biased for rotating beyondthat position. Accordingly, when the operating'arm 10 is returned to theunit operating position in the above described manner, the stop 82 islifted out of the recess. 78 and the spring 31 rotates the cam furthercounterclockwise or to the position of Fig. 2 for'insuring engage--merit of the periphery of the cam by the stop 82 when the evaporatortemperature decreases to the predetermined low temperature. Thus, thecontrol 8 is conditioned for normal operation until the lapse of anotherpredeterenemas mined cumulative amount of running time of the timingmechanism 44.

As pointed out above, my control 8 provides for independent adjustmentof both the normal operating and defrosting temperatures of therefrigerator. That is, through adjustments made to the tension of thetoggle spring 23 by turning the screw 29, the temperature ranges of eachof the settings of the knob 43 may be adjusted. Also, adjustments to thespacing etween the operating arm 10 and the magnet 84 as effected byturning the screw 86 determines the duration of and, therefore, theabnormally high temperature attained during each defrosting operation.

My control 8 further provides means whereby the user may manually set itin a permanently off position, enabling the user to shut down therefrigerator easily when its service is not required, as during vacationperiods. Additionally, my control 8 provides means whereby the user mayset it for fast freeze or continuous refrigerator operation during aheavy load period.

The means whereby the control may be set for off or fast freezecomprises a bellcrank S7 pivotally mounted as at 87:: on the sideportion 4-2 of the bracket 14 and including a forwardly projecting arm88. Carried on the arm 88 is an element 88a having portions straddlingthe arm 18 of the insulative member 17 secured to the side of theoperating arm 10. Another arm 89 of the bellcrank 87 is adapted forextending through a horizontal slot 9t, in the side wall of the liner 3in the manner shown in Fig. 1. Th extremity of the arm 89 is positionedin and cooperates with a cam slot 91 formed in the rear face of the knob43. The cam slot 91 is such that in the normal range of control settingof the knob 43, it cooperates with the bellcrank 87 to maintain theelement 88a in the position of Figs. 25. In this position the element 88has no effect on the movement on the operating arm 10 and the control 8operates normally for cyclically operating the refrigerating unit andperiodically initiating defrosting operations.

When it is desired to shut down the refrigerator, the control may be setin its permanently off position by turning the knob 43 to its mostcounterclockwise position in Fig. 2 to cause an outwardly extendingportion 92 of the cam slot 91 to cooperate with the arm 39 of thebellcrank 87. This results in a counterclockwise actuation of thebellcrank 87 and the element 88a which moves the operating arm 10 out ofits first or operating position and opens the unit contacts 21 if theoperating arm is in its first position when the control knob 43 is setin the off position. Until this setting is changed, the element 83aremains so positioned that it obstructs movement of the operating arm toits first position and thereby prevents restarting of the refrigeratingunit. If the knob 43 should be set in the off position when theoperating arm 10 is in its intermediate position or in the second ordefrosting position, the resultant actuation of the element 88a has noimmediate effect thereon. However, subsequently and until the knobsetting is changed, the element 88a obstructs movement of the operatingarm to its first position and thereby prevents closing of the unitscontacts 21 and restarting of the refrigerating unit.

To set the control for fast-freeze and thereby provide continuousrefrigerator operation during heavy load periods, the knob 43 may beturned to its most clockwise position in Fig. 2. This causes an inwardlyextending portion 93 of the cam slot 1 to cooperate with the arm 89 ofthe bellcrank and actuate the bellcrank and the element 88a clockwisefrom the position of Figs. 25 to a position in which the element 88aengages the arm 18 of the member 17 and maintains the operating arm 10in its first or unit operating position in which the unit contacts 21are closed. Until the knob 43 is turned out of this setting, therefrigerating unit operates continuously and provides fast-freezing.

By means of this last described feature of my control,

the user may manually terminate a defrosting operation and reset thecontrol for normal unit operation which it may be desired to do if forinstance a defrosting operation is initiated while a frozen dessert orthe like is being prepared or when a plenteous supply of ice cubes isrequired. This the user may accomplish simply by turning the knob 43 tothe fast-freezing position and then returning it to one of the normalsetting positions. This causes the element 88a to actuate the operatingarm 10 to its first position whereby the stop 82 thereon is lifted outof the cam recess 73 permitting further counterclockwise rotation of thecam by the spring 81 and conditioning the control for normal operationuntil the lapse of another predetermined cumulative amount of door opentime during unit running time.

It will be seen that while I prefer initiating the defrosting operationas a function of door open time during unit running time, my control 8could be modified to initiate the defrosting operation as a function ofjust time, of accumulative unit running time, or of cumulative door opentime.

By omitting both of the braking elements 74 and '75, the timingmechanism 44 would be caused to run at all times. After a predeterminedrunning time, for example 24 hours, the recess 78 in the cam 77 would bedriven into alignment with the stop 82 on the operating arm 10. If theoperating arm 10 were in the intermediate unit deenergizing positionwhen this alignment occurred the stop would simply fall into the recessand the operating arm would move to its defrosting position under theinfluence of the spring 23. If the operating arm 10 were in its first oroperating position when the alignment occurred, the spring 81 would snapthe hammer element 79 into engagement with the semi-circular arm 83 andthereby drive the operating arm into the defrosting position. Thedefrosting operation would be terminated in the same manner as describedabove.

The timing mechanism could also be caused to run at all times when therefrigerating unit is operating and defrosting would be initiated as afunction of cumulative unit running time. This could be accomplished byretaining the braking element 74 and omitting the door operated brakingelement 75. In such an arrangement, the timing mechanism 44 would drivethe cam 77 only during unit running time. After a predeterminedcumulative amount of running time of the timing mechanism 44, equal tothe cumulative unit running time, the recess 78 in the cam 77 would bealigned with the stop 32 on the operating arm 10. Again, if theoperating arm 10 were in the intermediate unit deenergizing positionwhen this alignment occurred, the stop would simply fall into the recessand the operating arm would move into its defrosting position under theinfluence of the spring 23 and if the operating arm were in its first oroperating position when the alignment occurred, the spring 81 would snapthe hammer element into engagement with the semi-circular arm 83 andthereby drive the operating arm into the defrosting position. In thisform also, the defrosting operation would be terminated in the samemanner as described above with regard to the preferred embodiment.

If it is desired to initiate defrosting as a function of cumulative dooropened time, my control 8 could be modified by retaining the dooroperated braking element 75 and omitting the braking element 74. In thisform the timing mechanism 44 would drive the cam 77 whenever therefrigerator door 6 stood open. After a predetermined cumulative amountof running time of the timing mechanism 44 equal to the cumulative dooropen time, the cam recess 77 would be aligned with the stop on theoperating arm. In this form also, if the operating arm were in theintermediate unit deenergizing position when this alignment occurred,the stop would simply fall into the recess and the operating arm wouldmove to its defrosting position under the influence of the spring 23. Ifthe operating arm were in its first or operating position when thealignment occurred, the spring 81 would snap the hammer element 79 intoengagement with the semi=circular arm 83 and thereby drive the operatingarm into the defrosting position. In this form also, the defrostingoperation would be terminated in the manner described above with respectto the preferred embodiment.

It will be seen further that while I refer to the contacts 22 as defrostheater contacts, they could be employed for controlling other defrostingmeans. For instance, they could control a solenoid valve in a reversecycle system and effect defrosting by opening the valve and applying hotrefrigerant to the evaporator in the system when the operating arm is inits second or defrosting position.

While I have shown and described a specific-embodiment of my invention,I do not desire my invention to be limited to the particular form shownand described, and I intend by the appended claims to cover allmodifications within the spirit and scope of my invention.

What I claim as new and desire to secure by Letters Patent of the UnitedStates is:

1. In a refrigerator including a door, a refrigerating unit anddefrosting means, automatic refrigerator controlling means comprising;an arm movable between a first and a second position, said arm effectingoperation of said refrigerating unit in said first position andenergization of said defrosting means in said second position,temperature responsive means actuating said arm to said first positionat a predetermined normally high temperature and toward said secondposition at a predetermined low temperature, a spring powered timingmechanism, means responsive to refrigerator door openings for windingsaid timing mechanism, and means operated by said timing mechanismintercepting said arm at a unit deener- ,gizing position intermediatesaid first and second posi .tions when said temperature decreases tosaid predeterminedlow temperature until alapse of a predeterminedcumulative amount of running time of said timing mechanism.

2. .In a refrigerator including a door, a refrigerating unit anddefrosting means, automatic refrigerator controlling means comprising;an arm movable between a .first and a second position, said armeffecting operation of said refrigerating unit in said first positionand energization of said defrosting means in said second position,temperature responsive means actuating'said arm to said first positionat a predetermined normally'high temperature and toward said secondposition at a'predetermincd low temperature, a springpowered timingiriechanism, means responsive to refrigerator door openings for windingsaid timing mechanism, means stopping said timing trolling meanscomprising; an arm movable between a first and a second position, saidarm elfecting'opera'tion of said refrigerating unit in saidfirstposition and energization of said defrosting means in said secondposition,

temperature responsive means actuating said arm tofsaid first positionat a predetermined normally high tempera- 'ture and toward said secondposition at a predetermined low temperature, a spring powered timingmechanism, means responsive to refrigerator door openings winding saidtiming mechanism, means stopping said timing mechanism when said door isclosed, and means operated by "said timing mechanism intercepting saidarm at a unit *deenergizing position intermediate said first and second-positions "when saidtemperaturedecreases to said predetermined lowtemperature until a lapseof: a .predeter- 10 mined cumulative amount ofrunningtimeof said timing mechanism.

4. In a refrigerator including a door, a refrigerating unit anddefrosting means, automatic refrigerator controlling means comprising;an arm movable between a first and a second position, said arm effectingoperation of said refrigerating unit in said first position andenergization of said defrosting means in'said second position,temperature responsive means actuating said arm to said first positionat a predetermined normally high temperature and toward said secondposition at a predetermined low temperature, a spring powered timingmechanism, means responsive to refrigerator door openings winding saidtiming mechanism, means stopping said timing mechanism when either saidarm is out of said first position or said refrigerator door is closed,and means operated by said timing mechanism intercepting said arm at aunit deenergizing position intermediate said first and second positionswhen said temperature decreases below said predetermined low temperatureuntil a lapse of a predetermined cumulative amount of running time ofsaid timing mechanism.

5. in a refrigerator including a door, a refrigerating unit anddefrosting means, automatic refrigerator controlling means comprising;an arm movable between a first and a second position, said arm effectingoperation of said refrigerating unit in said first position andenergization of said defrosting means in said second position,temperature responsive means actuating said arm to said first positionat a predetermined normally high temperature and toward said secondposition at a predetermined low temperature, a spring powered timingmechanism, means responsive to refrigerator door openings winding saidtiming mechanism, means operated by said timing mechanism normallyintercepting said arm at a unit deenergizing position intermediate saidfirst and second positions when said temperature decreases to saidpredetermined low temperature, said last-mentioned means permittingmovement of said arm to said second position upon a lapse of apredetermined cumulative amount of running time of said timingmechanism, and a magnet attracting said arm when in said secondposition, the attraction of said magnet being overcome and said armbeing returned to said first position by said temperature responsivemeans at a predetermined abnormally high temperature.

6. In a. refrigerator including a door, a refrigerating unit anddefrosting means, automatic refrigerator controlling means comprising;an arm movable between a first and a secondposition, said arm effectingoperation of said refrigerating unit in said first'position andenergization of said defrosting means in said second position,temperature responsive means actuating said arm to said first positionat a predetermined normally high temperature and toward said secondposition at a predetermined low temperature, a spring powered timingmechanism, means responsive to refrigerator door openings winding saidtiming mechanism, means stopping said timing mecha nism when said arm isout of said first position, means operated by said timing mechanismnormally intercepting said arm at a unit deenergizing positionintermediate said first and second positions when said temperaturedecreases to said predetermined low emperature, said lastmentioned meanspermitting movement of said arm to said second position upon a lapse ofa predetermined cumulative amount of running time of said timingmechanism, and a magnet attracting said arm when in said secondposition, the attraction of said magnet being overcome and said armbeing returned to, said first position by said temperature responsivemeans at a predetermined abnormally high temperature.

7. In a refrigerator including a door, a refrigerating unit anddefrosting means, automatic refrigerator controlling means comprising;an .arm movable between a first and a second position,;said armeffecting operation ofsaid refrigerating unit in said first positionand, energization of said defrosting means in said second position,temperature responsive means actuating said arm to said first positionat a predetermined normally high temperature and toward said secondposition at a predetermined low temperature, a spring powered timingmechanism, means responsive to refrigerator door openings winding saidtiming mechanism, means stopping said timing mechanism when said door isclosed, means operated by said timing mechanism normally interceptingsaid arm at a unit deenergizing position intermediate said first secondpositions when said temperature decreases to said predetermined lowtemperature, said last-mentioned means permitting movement of said armto said second position upon a lapse of a predetermined cumulativeamount of running time of said timing mechanism, and a magnet attractingsaid arm when in said second position, the attraction of said magnetbeing overcome and said arm being returned to said first position bysaid temperature responsive means at a predetermined abnormally hightemperature.

8. In a refrigerator including a door, a refrigerating unit anddefrosting means, automatic refrigerator controlling means comprising;an arm movable between a first and a second position, said arm effectingoperation of said refrigerating unit in said first position andenergizetion of said defrosting means in said second position,temperature responsive means actuating said arm to said first positionat a predetermined normally high temperature and toward said secondposition at a predetermined low temperature, a spring powered timingmechanism, means responsive to refrigerator door openings winding saidtiming mechanism, means stopping said timing mechanism when either saidarm is out of said first position or said refrigerator door is closed,means operated by said timing mechanism normally intercepting said armat a unit deenergizing position intermediate said first and secondpositions when said temperature decreases to said predetermined lowtemperature, said last-mentioned means permitting movement of said armto said second position upon a lapse of a predetermined cumulativeamount of running time of said timing mechanism, and a magnet attractingsaid arm when in said second position, the attraction of said magnetbeing overcome and said arm being returned to said first position bysaid temperature responsive means at a predetermined abnormally hightemperature.

9. In a refrigerator including a door, a refrigerating unit anddefrosting means, automatic refrigerator controlling means comprising;an arm movable between a first and a second position, said arm effectingoperation of said refrigerating unit in said first position andenergization of said defrosting means in said second position,temperature responsive means actuating said arm to said first positionat a predetermined normally high temperature and toward said secondposition at a predetermined low temperature, a spring powered timingmechanism, means responsive to refrigerator door openings winding saidtiming mechanism, and means operated by said timing mechanism normallyintercepting said arm at a unit deenergizing position intermediate saidfirst and second positions when said temperature decreases to saidpredetermined low temperature, said last-mentioned means actuating saidarm from said first position to said second position if said arm is insaid first position upon a lapse of a predetermined cumulative amount ofrunning time of said timing mechanism.

10. In a refrigerator including a door, a refrigerating unit anddefrosting means, automatic refrigerator con trolling means comprising;an arm movable between a first and a second position, said arm effectingoperation of said refrigerating unit in said first position andenergization of said defrosting means in said second position,temperature responsive means actuating said arm to said first positionat a predetermined normally high temperature and toward said secondposition at a predetermined low temperature, a spring powered timingmechanism, means responsive to refrigerator door openings winding saidtiming mechanism, means stopping said timing mechanism when said arm isout of said first position, and means operated by said timing mechanismnormally intercepting said arm at a unit deenergizing positionintermediate said first and second positions when said temperaturedecreases to said predetermined low temperature, said last-mentionedmeans actuating said arm from said first position to said secondposition upon a lapse of a predetermined cumulative amount of runningtime of said timing mechanism.

11. In a refrigerator including a door, a refrigerating unit anddefrosting means, automatic refrigerator controlling means comprising;an arm movable between a first and a second position, said arm effectingoperation of said refrigerating unit in said first position andenergization of said defrosting means in said second position,temperature responsive means actuating said arm to said first positionat a predetermined normally high temperature and toward said secondposition at a predetermined low temperature, a spring powered timingmechanism, means responsive to refrigerator door openings Winding saidtiming mechanism, means stopping said timing mechanism when said door isclosed, and means operated by said timing mechanism normallyintercepting said arm at a unit deenergizing position intermediate saidfirst and second positions when said temperature decreases to saidpredetermined low temperature, said last-mentioned means actuating saidarm from said first position to said second position if said arm is insaid first position upon a lapse of a predetermined cumulative amount ofrunning time of said timing mechanism.

12. In a refrigerator including a door, a refrigerating unit anddefrosting means, automatic refrigerator controlling means comprising;an arm movable between a first and a second position, said arm effectingoperation of said refrigerating unit in said first position andenergization of said defrosting means in said second position,temperature responsive means actuating said arm to said first positionat a predetermined normally high temperature and toward said secondposition at a predetermined low temperature, a spring powered timingmechanism, means responsive to refrigerator door openings winding saidtiming mechanism, means stopping said timing mechanism when either saidarm is out of said first position or said refrigerator door is closed,and means operated by said timing mechanism normally intercepting saidarm at a unit deenergizing position intermediate said first and secondpositions when said temperature decreases to said predetermined lowtemperature, said last-mentioned means actuating said arm from saidfirst position to said second position upon a lapse of a predeterminedcumulative amount of running time of said timing mechanism.

13. In a refrigerator including a door, a refrigerating unit anddefrosting means, automatic refrigerator controlling means comprising;an arm movable between a first and a second position, said arm effectingoperation of said refrigerating unit in said first position andenergization of said defrosting means in said second position,temperature responsive means actuating said arm to said first positionat a predetermined normally high temperature and toward said secondposition at a predetermined low temperature, a spring powered timingmechanism, means responsive to refrigerator door openings winding saidtiming mechanism, means operated by said timing mechanism normallyintercepting said arm at a unit de energizing position intermediate saidfirst and second positions when said temperature decreases to saidpredetermined low temperature, said last-mentioned means actuating saidarm from said first position to said second position if said arm is insaid first position upon a lapse of a predetermined cumulative amount ofrunning time of said timing mechanism, and a magnet attracting said armin said second position, the attraction of said magnet beingovercome'and 'said arrn being returned tosaid first position by saidtemperature responsive means at a predetermined abnormally hightemperature.

14. In a refrigerator including a door, a refrigerating unit anddefrosting means, automatic refrigerator controlling means comprising;an arm movable between a first and a second position, said arm effectingoperation of said refrigerating unitinsaid first position andenergization of said defrosting means in said second position,

temperature responsive means actuating'said arm to said first positionat a predetermined normally high temperature and toward said secondposition at a predetermined low temperature, a spring powered timingmechanism, means responsive to refrigerator door openings'winding saidtiming mechanism, means stopping said timing mechanism when said arm isout of said first position, means operated by said timing mechanismnormally intercepting said arm at a unit deenergizing positionintermediate said first and second positions when said temperaturedecreases to said predetermined low temperature, said last-mentionedmeans actuatingsaid arm from said firstposition to said second positionupon a lapse of a predetermined cumulative amount of running time ofsaid'timing mechanism, and a magnet attracting said arm in said secondposition, the attraction of said magnet being overcome and said armbeing returned to said first position by said temperature responsivemeans at a predetermined abnormally high temperature.

15. In a refrigerator including a door, a refrigerating unit anddefrosting means, automatic refrigerator controlling means comprising;an arm movable between a first and a second position, said arm efiectingoperation of said refrigerating unit in said first position andenergization of said defrosting means in said second position,temperature responsive means actuating said arm to said first positionat a predetermined normally high temperature and toward said secondposition at a predetermined low temperature, a spring powered timingmechanism, means responsive to refrigerator door openings winding saidtiming mechanism, means stopping said timing mechanism when said door isclosed, means operated by said timing mechanism normally interceptingsaid arm at a unit deenergizing position intermediate said first and second positions when said temperature decreases to said predetermined lowtemperature, said last-mentioned means actuating said arm from saidfirst position to said second position if said arm is in said firstposition upon a lapse of a predetermined cumulative amount of runningtime of said timing mechanism, and a magnet attracting said arm in saidsecond position, the attraction of said magnet being overcome and saidarm being returned to said first position by said temperature responsivemeans at a predetermined abnormally high temperature.

16. in a refrigerator including a door, a refrigerating unit anddefrosting means, automatic refrigerator controlling means comprising;an arm movable between a first and a second position, said arm eifectingoperation of said refrigerating unit in said first position andenergization of said defrosting means in said second position,temperature responsive means actuating said arm to said first positionat a predetermined normally high temperature and toward said secondposition at a predetermined low temperature, a spring powered timingmechanism, means responsive to refrigerator door openings winding saidtiming mechanism, means stopping said timing mechanism when either saidarm is out of said first position or said refrigerator door is closed,means operated by said timing mechanism normally intercepting said armat a unit deenergizing position intermediate said first and secondpositions when said temperature decreases to said predetermined lowtemperature, said last-mentioned means actuating said arm from saidfirst position to said second position upon a lapse of a predeterminedcumulative amount of running time of said timing mechanism, and a magnetattracting said arm in said second position, the

attraction of said-magnet being overcome and said arm being returnedtosaid first position by said temperature responsive means at apredetermined abnormally high temperature.

17. In a refrigerator including a door, a refrigerating unit anddefrosting means, automatic refrigerator controlling means comprising;an arm movable between a first and a second position, said arm effectingoperation of said refrigerating unit in said first position andenergization of said defrosting means in said second position,temperature responsive means actuating said arm to said first positionat a predetermined normally high temperature and toward said secondposition at a predetermined low temperature, a spring powered timingmechanism,

means responsive to refrigerator door openings winding said timingmechanism, a rotatable cam driven by said timing mechanism, said camnormally intercepting said arm at a unit deenergizing positionintermediate said first and second positions when said temperaturedecreases to said predetermined low temperature, said cam permittingmovement of said arm to said second position upon a lapse of apredetermined cumulative amount of running time of said timingmechanism, a hammer element carried by said cam, an overcenter springeffective upon said lapse of time for actuating said hammer element todrive said arm into said second position if said arm is in said firstposition 'upon said lapse of said time, and a magnet attracting said armwhen in said second position, the attraction of said magnet beingovercome and said arm being returned to said first position by saidtemperature responsive means at a predetermined abnormally hightemperature.

18. In a refrigerator including a door, a refrigerating unit anddefrosting means, automatic refrigerator controlling means comprising;an arm movable between a first and a second position, said arm effectingoperation of said refrigerating unit in said first position andenergization of said defrosting means in said second position,temperature responsive means actuating said arm to said first positionat a predetermined normally high temperature and toward said secondposition at a predetermined low temperature, a spring powered timingmechanism including a balance wheel, means responsive to refrigeratordoor openings winding said timing mechanism, a braking element carriedby said arm, said braking element engaging said balance wheel andstopping said timing mechanism when said arm is out of said firstposition, said braking element providing a starting impetus for saidbalance Wheel when said arm returns to said first position, a rotatablecam driven by said timing mechanism, said cam normally intercepting saidarm at a unit deenergizing position intermediate said first and secondpositions when said temperature decreases to said predetermined lowtemperature, said cam permitting movement of said arm to said secondposition upon a lapse of a predetermined cumulative amount of runningtime of said timing mechanism, a hammer element carried by said cam, anovercenter spring effective upon said lapse of time for actuating saidhammer element to drive said arm into said second position, and a magnetattracting said arm when in said second position, the attraction of saidmagnet being overcome and said arm being returned to said first positionby said temperature responsive means at a predetermined abnormally hightemperature.

19. in a refrigerator including a door, a refrigerating unit anddefrosting means, automatic refrigerator controlling means comprising;an arm movable between a first and a second position, said arm effectingoperation of said refrigerating unit in said first position andenergization of said defrosting means in said second position,temperature responsive means actuating said arm to said first positionat a predetermined normally high temperature and toward said secondposition at a predetermined low temperature, a spring powered timingmechanism including a balance wheel, a door operated plunger adapted forwinding said timing mechanism, a braking element carried by saidplunger, said braking element engaging said balance wheel and stoppingsaid timing mechanism when said door is closed, said braking elementproviding a starting impetus for said balance wheel when said door isopened, a rotatable cam driven by said timing mechanism, said camnormally intercepting said arm at a unit deenergizing positionintermediate said first and second positions when said temperaturedecreases to said predetermined low temperature, said cam permittingmovement of said arm to said second position upon a lapse of apredetermined cumulative amount of running time of said timingmechanism, a hammer element carried by said cam, an overcenter springefiective upon said lapse of time for actuating said hammer element todrive said arm into said second position if said arm is in said firstposition upon said lapse of time, and a magnet attracting said arm whenin said second position, the attraction of said magnet being overcomeand said arm being returned to said first position by said temperatureresponsive means at a predetermined abnormally high temperature.

20. in a refrigerator including a door, a refrigerating unit anddefrosting means, automatic refrigerator controlling means comprising;an arm movable between a first and a second position, said arm effectingoperation of said refrigerating unit in said first position andenergization of said defrosting means in said second position,temperature responsive means actuating said arm to said first positionat a predetermined normally high temperature and toward said secondposition at a predetermined low temperature, a spring powered timingmechanism including a balance wheel, a door operated plunger adapted forwinding said timing mechanism, a braking element carried by said arm,said braking element engaging said balance wheel and stopping saidtiming mechanism when said arm is out of said first position anddisengaging said balance wheel and providing a starting impetus thereforwhen said arm is returned to said first position, another brakingelement carried by said plunger, said last-mentioned braking elementengaging said balance wheel and stopping said timing mechanism when saiddoor is closed and disengaging said balance wheel and providing astarting impetus therefor when said door is opened, a rotatable camdriven by said timing mechanism, said cam normally intercepting said armat a unit deenergizing position intermediate said first and secondpositions when said temperature decreases to said predetermined lowtemperature, said cam permitting movement of said arm to said secondposition upon a lapse of a predetermined cumulative amount of runningtime of said timing mechanism, a hammer element carried by said cam, anovercenter spring effective upon said lapse of time for actuating saidhammer element to drive said arm into said second position, and a magnetattracting said arm when in said second position, the attraction of saidmagnet being overcome and said arm being returned to said first positionby said temperature responsive means at a predetermined abnormally hightemperature.

References Cited in the file of this patent UNITED STATES PATENTS2,064,396 Volpin Dec. 15, 1936 2,463,027 Frie Mar. 1, 1949 2,530,985Morrison Nov. 21, 1950 2,595,967 McCloy May 6, 1952 2,612,026 HansenSept. 30, 1952

